The BIOS on the motherboard will always perform a power-on-self-test “POST” during power up, usually this test is perform to ensure proper system function and if a failure occurs – the “POST” will identify the failure and emits a beeping sound to prompt the service technician to take corrective action ASAP.

The exact meaning of the beeping codes varies from different BIOS developers, there are 3 basic BIOS developer today, the most popular BIOS is made by “American Mega-trend” - AMI, Award and Phoenix BIOS. The beep codes for this AMI & Award BIOS developer are provided in this memory troubleshooter guide, we do not provide beep code reference for Phoenix BIOS and custom BIOS written by other companies other than the two mention.

Beep codes are not entirely consistent sometimes to detect the exact failures, but generally it is still the most dependent methods to diagnose a fault without opening up the PC system or using any diagnostic software.